"You have a valid reason for troubling me, I suppose, Mr. Grodman?" said the Home Secretary, almost cheerfully. "Of course it is about Mortlake?"

 

"It is; and I have the best of all reasons."

 

"Take a seat. Proceed."

 

"Pray do not consider me impertinent, but have you ever given any attention to the science of evidence?"

 

"How do you mean?" asked the Home Secretary, rather puzzled, adding, with a melancholy smile, "I have had to lately. Of course, I've never been a criminal lawyer, like some of my predecessors. But I should hardly speak of it as a science; I look upon it as a question of common-sense."

 

"Pardon me, sir. It is the most subtle and difficult of all the sciences. It is, indeed, rather the science of the sciences. What is the whole of Inductive Logic, as laid down, say, by Bacon and Mill, but an attempt to appraise the value of evidence, the said evidence being the trails left by the Creator, so to speak? The Creator has--I say it in all reverence--drawn a myriad red herrings across the track, but the true scientist refuses to be baffled by superficial appearances in detecting the secrets of Nature. The vulgar herd catches at the gross apparent fact, but the man of insight knows that what lies on the surface does lie."

 

"Very interesting, Mr. Grodman, but really--"

 

"Bear with me, sir. The science of evidence being thus so extremely subtle, and demanding the most acute and trained observation of facts, the most comprehensive understanding of human psychology, is naturally given over to professors who have not the remotest idea that 'things are not what they seem,' and that everything is other than it appears; to professors, most of whom by their year-long devotion to the shop-counter or the desk, have acquired an intimate acquaintance with all the infinite shades and complexities of things and human nature. When twelve of these professors are put in a box, it is called a jury. When one of these professors is put in a box by himself, he is called a witness. The retailing of evidence--the observation of the facts--is given over to people who go through their lives without eyes; the appreciation of evidence--the judging of these facts--is surrendered to people who may possibly be adepts in weighing out pounds of sugar. Apart from their sheer inability to fulfil either function--to observe, or to judge--their observation and their judgment alike are vitiated by all sorts of irrelevant prejudices."

 

"You are attacking trial by jury."

 

"Not necessarily. I am prepared to accept that scientifically, on the ground that, as there are, as a rule, only two alternatives, the balance of probability is slightly in favour of the true decision being come to. Then, in cases where experts like myself have got up the evidence, the jury can be made to see through trained eyes."

 

The Home Secretary tapped impatiently with his foot.

 

"I can't listen to abstract theorising," he said. "Have you any fresh concrete evidence?"

 

"Sir, everything depends on our getting down to the root of the matter. What percentage of average evidence should you think is thorough, plain, simple, unvarnished fact, 'the truth, the whole truth, and nothing but the truth'?"

 

"Fifty?" said the Minister, humouring him a little.

 

"Not five. I say nothing of lapses of memory, of inborn defects of observational power--though the suspiciously precise recollection of dates and events possessed by ordinary witnesses in important trials taking place years after the occurrences involved, is one of the most amazing things in the curiosities of modern jurisprudence. I defy you, sir, to tell me what you had for dinner last Monday, or what exactly you were saying and doing at five o'clock last Tuesday afternoon. Nobody whose life does not run in mechanical grooves can do anything of the sort; unless, of course, the facts have been very impressive. But this by the way. The great obstacle to veracious observation is the element of prepossession in all vision. Has it ever struck you, sir, that we never _see_ any one more than once, if that? The first time we meet a man we may possibly see him as he is; the second time our vision is coloured and modified by the memory of the first. Do our friends appear to us as they appear to strangers? Do our rooms, our furniture, our pipes strike our eye as they would strike the eye of an outsider, looking on them for the first time? Can a mother see her babe's ugliness, or a lover his mistress's shortcomings, though they stare everybody else in the face? Can we see ourselves as others see us? No; habit, prepossession changes all. The mind is a large factor of every so-called external fact. The eye sees, sometimes, what it wishes to see, more often what it expects to see. You follow me, sir?"

 

The Home Secretary nodded his head less impatiently. He was beginning to be interested. The hubbub from without broke faintly upon their ears.

 

"To give you a definite example. Mr. Wimp says that when I burst open the door of Mr. Constant's room on the morning of December 4th, and saw that the staple of the bolt had been wrested by the pin from the lintel, I jumped at once to the conclusion that I had broken the bolt. Now I admit that this was so, only in things like this you do not seem to _conclude_, you jump so fast that you _see_, or seem to. On the other hand, when you _see_ a _standing_ ring of fire produced by whirling a burning stick, you do _not_ believe in its continuous existence. It is the same when witnessing a legerdemain performance. Seeing is not always believing, despite the proverb; but believing is often seeing. It is not to the point that in that little matter of the door Wimp was as hopelessly and incurably wrong as he has been in everything all along. The door _was_ securely bolted. Still I confess that I should have seen that I had broken the bolt in forcing the door, even if it had been broken beforehand. Never once since December 4th did this possibility occur to me, till Wimp with perverted ingenuity suggested it. If this is the case with a trained observer, one moreover fully conscious of this ineradicable tendency of the human mind, how must it be with an untrained observer?"

 

"Come to the point, come to the point," said the Home Secretary, putting out his hand as if it itched to touch the bell on the writing-table.

 

"Such as," went on Grodman, imperturbably, "such as--Mrs. Drabdump. That worthy person is unable, by repeated violent knocking, to arouse her lodger who yet desires to be aroused; she becomes alarmed, she rushes across to get my assistance; I burst open the door--what do you think the good lady expected to see?"

 

"Mr. Constant murdered, I suppose," murmured the Home Secretary, wonderingly.

 

"Exactly. And so she saw it. And what should you think was the condition of Arthur Constant when the door yielded to my violent exertions and flew open?"

 

"Why, was he not dead?" gasped the Home Secretary, his heart fluttering violently.

 

"Dead? A young, healthy fellow like that! When the door flew open, Arthur Constant was sleeping the sleep of the just. It was a deep, a very deep sleep, of course, else the blows at his door would long since have awakened him. But all the while Mrs. Drabdump's fancy was picturing her lodger cold and stark, the poor young fellow was lying in bed in a nice warm sleep."

 

"You mean to say you found Arthur Constant alive?"

 

"As you were last night."

 

The Minister was silent, striving confusedly to take in the situation. Outside the crowd was cheering again. It was probably to pass the time.

 

"Then, when was he murdered?"

 

"Immediately afterwards."

 

"By whom?"

 

"Well, that is, if you will pardon me, not a very intelligent question. Science and common-sense are in accord for once. Try the method of exhaustion. It must have been either by Mrs. Drabdump or myself."

 

"You mean to say that Mrs. Drabdump--!"

 

"Poor dear Mrs. Drabdump, you don't deserve this of your Home Secretary! The idea of that good lady!"

 

"It was _you_!"

 

"Calm yourself, my dear Home Secretary. There is nothing to be alarmed at. It was a solitary experiment, and I intend it to remain so." The noise without grew louder. "Three cheers for Grodman! Hip, hip, hip, hooray," fell faintly on their ears.

 

But the Minister, pallid and deeply moved, touched the bell. The Home Secretary's home secretary appeared. He looked at the great man's agitated face with suppressed surprise.

 

"Thank you for calling in your amanuensis," said Grodman. "I intended to ask you to lend me his services. I suppose he can write shorthand."

 

The Minister nodded, speechless.

 

"That is well. I intend this statement to form the basis of an appendix to the twenty-fifth edition--sort of silver wedding--of my book, _Criminals I have Caught_. Mr. Denzil Cantercot, who, by the will I have made to-day, is appointed my literary executor, will have the task of working it up with literary and dramatic touches after the model of the other chapters of my book. I have every confidence he will be able to do me as much justice, from a literary point of view, as you, sir, no doubt will from a legal. I feel certain he will succeed in catching the style of the other chapters to perfection."

 

"Templeton," whispered the Home Secretary, "this man may be a lunatic. The effort to solve the Big Bow Mystery may have addled his brain. Still," he added aloud, "it will be as well for you to take down his statement in shorthand."

 

"Thank you, sir," said Grodman, heartily. "Ready, Mr. Templeton? Here goes. My career till I left the Scotland Yard Detective Department is known to all the world. Is that too fast for you, Mr. Templeton? A little? Well, I'll go slower; but pull me up if I forget to keep the brake on. When I retired, I discovered that I was a bachelor. But it was too late to marry. Time hung heavy on my hands. The preparation of my book, _Criminals I have Caught_, kept me occupied for some months. When it was published, I had nothing more to do but think. I had plenty of money, and it was safely invested; there was no call for speculation. The future was meaningless to me; I regretted I had not elected to die in harness. As idle old men must, I lived in the past. I went over and over again my ancient exploits; I re-read my book. And as I thought and thought, away from the excitement of the actual hunt, and seeing the facts in a truer perspective, so it grew daily clearer to me that criminals were more fools than rogues. Every crime I had traced, however cleverly perpetrated, was from the point of view of penetrability a weak failure. Traces and trails were left on all sides--ragged edges, rough-hewn corners; in short, the job was botched, artistic completeness unattained. To the vulgar, my feats might seem marvellous--the average man is mystified to grasp how you detect the letter 'e' in a simple cryptogram--to myself they were as commonplace as the crimes they unveiled. To me now, with my lifelong study of the science of evidence, it seemed possible to commit not merely one but a thousand crimes that should be absolutely undiscoverable. And yet criminals would go on sinning, and giving themselves away, in the same old grooves--no originality, no dash, no individual insight, no fresh conception! One would imagine there were an Academy of crime with forty thousand armchairs. And gradually, as I pondered and brooded over the thought, there came upon me the desire to commit a crime that should baffle detection. I could invent hundreds of such crimes, and please myself by imagining them done; but would they really work out in practice? Evidently the sole performer of my experiment must be myself; the subject--whom or what? Accident should determine. I itched to commence with murder--to tackle the stiffest problems first, and I burned to startle and baffle the world--especially the world of which I had ceased to be. Outwardly I was calm, and spoke to the people about me as usual. Inwardly I was on fire with a consuming scientific passion. I sported with my pet theories, and fitted them mentally on every one I met. Every friend or acquaintance I sat and gossiped with, I was plotting how to murder without leaving a clue. There is not one of my friends or acquaintances I have not done away with in thought. There is no public man--have no fear, my dear Home Secretary--I have not planned to assassinate secretly, mysteriously, unintelligibly, undiscoverably. Ah, how I could give the stock criminals points--with their second-hand motives, their c............